Ever since tableware was invented, there has been a need to keep food warm after being served, this is not only true for the food that is served on dishes (plates) which are practically impossible to insulate, but also other foodstuffs such as bread, tortillas, beverages, etc.
This need is specially noticed in restaurants, hospitals, etc. where it takes a relatively long period time between the time the food is served and the time the food is delivered and consumed.
At home this need to keep food hot is most apparent in cold climate places. In warm places this need may be overlooked because of the paradigm that there is no practical or easy solution to the problem but the enjoyment of eating is definitely increased when the food is eaten slowly at the appropriate temperature getting satisfied by eating less food while socializing with family or friends.
In restaurants they try to solve the problem by pre-heating the dishes (plates), and in some steak restaurants they use metal skillets with a wooden base.
In hospitals they use expensive and complicated carriers (plate warmers or bases with covers), but as soon as the cover is taken off the food cools down rapidly.
At home very few people attempt to solve the problem, there is a paradigm that no practical solution exists, some people preheat the plates on special occasions, but the handling of hot dishes is complicated and cumbersome and they do not stay hot for very long.
The pre-heated dishes in restaurants do not stay hot for very long and have to be handled with mittens or some form of protection to avoid burns because the rim also gets very hot. The skillets have a very limited use (almost only for steaks), they have to be heated to a very high temperature and they lose the heat very fast, they are also very expensive and impractical for use at home.
My heat storage device incorporated in the design of a dish (plate) is a more elegant, efficient and above all less expensive solution than skillets for steaks. It does not need to be over heated and it releases its thermal energy at a controlled rate
The carriers used in hospitals are only effective until the cover is removed, after that, the food cools down. They are not practical for use at home or at restaurants U.S. Pat. No. 6,188,053 by Wyatt shows a Heat retentive server this server (not a dish) is complex, even has a pressure relief valve, it is not practical for use in restaurants or at home
U.S. Pat. No. 4,246,884 by Vandas is a plate warmer (not a plate or dish) which is not practical for restaurants or for use at home, its temperature v. time chart shows that it needs to be heated at a very high temperature and the temperature declines very fast with time. My heat storage device incorporated into the design of a plate needs to be heated typically for only one minute in a 1200 Watts microwave oven, reaches a temperature of only about 200 degrees Fahrenheit, but still ends up with a temperature of about 140 degrees Fahrenheit after 20 to 25 minutes due to its controlled heat release rate (if preheated just 1:15 minutes, it stays hot for half an hour (140 degrees Fahrenheit after 30 minutes). A delay action is incorporated in the design to avoid over heating the food. This delay action can be specified as wished within a certain extent according to the particular purpose of the dish (steak, pasta, general purpose, etc.).
U.S. Pat. No. 2,545,733 by Hatfield is a water filled child dish, it is only practical for children and has to be refilled with hot water every time it is used, its use is very specific, not suitable for adults.
U.S. Application publication 2002/0096514A1 by Johnson shows a heat retaining microwaveable dish very complicated with too many components (even includes a filling spout of which no details are shown), this dish could be even dangerous if water is used as the heat retaining medium. Independently of which retaining medium is used, food may fall in the holes causing serious hygienic problems. My version of a heat retaining dish has only three elements including a rigid microwave absorbing heater(or heat retaining medium).
U.S. Pat. No. 5,052,369 by Johnson shows another heat retaining food container. There are a few more of these type of containers (not plates or dishes) but none of these inventions have the advantage of my heat storage device which is: microwaveable, efficient (absorbs energy fast and releases it at a controlled rate) and can be integrated (or incorporated) into the design of ceramic dishes, bowls, coffee mugs, etc.
In conclusion: while it is evident that the problem exists and there is a real need for a solution to this problem: Most of these inventions which attempt to solve the problem are very complicated and expensive, and none of them seem to be designed for use at home. My heat storage device incorporated to a dish can be handled normally by the rim which remains cool, and can be used at home on a regular basis. It is normally preheated only 1 to 1:15 minutes (my preferred embodiment is designed for just one minute pre-heating time), and this is normally enough, it stays hot for 20 to 30 minutes (Approximately 140 degrees Fahrenheit temperature after this elapsed time).
My integrated microwaveable heat storage device although my preferred embodiment is as a heat storing plate (dish), is not limited to the application on just dishes, but it has many other applications as shown below.
It is therefore an object of the invention to provide an easy to use microwaveable heat storage device that can either be used as an integral part of dishes, bowls, coffee mugs etc or independently. and also be used in other different applications (such as tortilla warmers, pizza delivery, etc.), mainly to keep food warm after being served or transported, in different sizes, masses predetermined cross-sectional shapes and forms according to the particular use required,
It is another object of the invention to absorb a relatively high amount of energy in a very short time (typically 1 to 1.5 minutes for a dish) and store it as heat in a rigid non-toxic heater with enough predetermined thermal mass in order to maintain food hot after being served and while it is delivered and consumed
It is another object of the invention to maintain the food warm by releasing the heat with a delayed action, at a controlled heat transfer rate and within a certain range of temperature without overheating it. This delayed action can be controlled mainly by varying internal dimensions such as the gap between the heater and the container (dish bowl, mug, etc.) which at present I prefer to be of the order of 2 to 4 millimeters for a dish.
It is another object of the invention to be applied in a multipurpose heat storage dish or plate (which is my preferred embodiment and one of the main practical applications of the heat-storage device) in which enough and predetermined thermal energy is stored without reaching very high temperatures (only about 200 degrees Fahrenheit) to allow enjoyment of the food and that can be safely handled by the rim which remains cool.
These are some of the unique features of this dish:
1) Absorbing a sufficient predetermined energy in a relatively short period of time (1 to 1:30 minutes, typically one minute.
2) Reaching maximum temperature on the surface several minutes after (and this is very important) removing it from the oven (delay action).
3) Releasing this heat at a controlled rate
4) And very important, the rim stays cool during this whole process allowing for safe handling.
It is another very important object of the invention to provide a dish with all of the advantages shown above at a low cost and for use at home regularly in a practical and easy way in order to improve eating habits, such as eating slowly, enjoying the food and getting satisfied by consuming less food (it is a well known fact that overeating is a real problem in our present society).
It is another object of the invention to provide a dish of choice (or favorite), a coffle mug of choice, etc. for the members of the family, since according to tests performed, the enjoyment of eating is increased, The family members tend to grow fond of this type of dish.
And finally, when the best of the cuisine (or style of cooking) is prepared and the recipe can not be improved, the quality of service still can be improved by serving the food in a dish that maintains the food at the ideal temperature in a very innovative manner